Great and great that Arnold is causing this. But if I was him and wanted to be a little devious, I might also announce that whatever the Mr. Olympia gets, the Arnold Champion from earlier that year will be paid $50,000 more retroactively the day after the Olympia. So if Mr. O this year gets $800K, Andrew Jacked would get another $100,000 the day after, so the Arnold Champion is always the highest paid.
Arnold did this 31 years ago, when he awarded $100,000 for the ASC, which matched the Olympia prize money at the time. Mike Francois was the first to win this much (I believe).
Of course, the IFBB/Weiders never really up the ante, unless competition forces them to do so. Recall that the first bodybuilding contest to offer $100K for 1st place was Vince McMahon's World Bodybuilding Federation (WBF) Championship. Gary Strydom got that in 1991 for his first win. In perspective, that's $40K more than what Lee Haney received ($60K) for his 1990 Olympia victory and $20K more than Haney's prize money ($80K) for his 1991 win.
Dorian was the first Mr. O to get $100K, matching what Strydom got for the second (and final) WBF championship.
Then the Olympia prize money went up to $110,000. When the IFBB came up with some stupid rule that no show could offer more $$$$ than the O, Arnold started giving awarding Hummers along with the green for winning his event. (Ronnie got the first of those in 2001).